amd64: Avoid creation of duplicate Projs at the Start node.
amd64: Avoid creation of duplicate Projs at the Start node.

Duplicate Projs are a problem when CSE is off, e.g. -O0.

jonashaag/libfirm,8l/libfirm,davidgiven/libfirm,MatzeB/libfirm,MatzeB/libfirm,davidgiven/libfirm,killbug2004/libfirm,killbug2004/libfirm,davidgiven/libfirm,jonashaag/libfirm,MatzeB/libfirm,jonashaag/libfirm,MatzeB/libfirm,killbug2004/libfirm,killbug2004/libfirm,libfirm/libfirm,davidgiven/libfirm,killbug2004/libfirm,libfirm/libfirm,MatzeB/libfirm,8l/libfirm,killbug2004/libfirm,davidgiven/libfirm,jonashaag/libfirm,jonashaag/libfirm,jonashaag/libfirm,MatzeB/libfirm,MatzeB/libfirm,davidgiven/libfirm,8l/libfirm,libfirm/libfirm,davidgiven/libfirm,8l/libfirm,killbug2004/libfirm,8l/libfirm,libfirm/libfirm,jonashaag/libfirm,8l/libfirm,8l/libfirm,libfirm/libfirm